Lightning-arrester.



No. 727,687 PATENTED MAY 12, 1903. H. E. RAYMOND. LIGHTNING ARRESTER.

N0 MODEL Fig.2;

. v lnvenfion '/i wd Henry B.Qagmond' \Afibnesses. '1 1 I Jqbb was so. mom umo WASHINGTON r UNITED STATES iatented May 12, 1903.

PATENT OFFICE.

HENRY E. RAYMOND, OF SCHENECTADY, NElV YORK, ASSIGNOR TO THE GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

LlGHTNlN G-ARRESTER.

SPECIFICATION formingpart (if Letters Patent No. 727,687, dated May 12, 1903.

Application filed July 22, 1899. Serial No. 724,770. (No model.)

To ctZZ whom it may concern:

Be it known that I, HENRY E. RAYMOND, a citizen of the United States,residing at Schenectady, in the county of Schenectady and State of New York,have invented certain new and useful Improvements in Lightning-Arresters, (Case No. 1,340,) of which the following is a specification.

This invention relates to improvements in lightning-arresters and embodies the results of observations extending over many years of the conduct of the same in heavy storms.

The invention consists in the combination of various elements the character and functions of which are described herein, and particularly pointed out in the claims.

Most of the trouble with inefficient lightning-arresters has been caused either by their having a too great striking distance or by the arcing of arresters having a lowbreakdown point. The gap must be the weakest part of the line with respect to a lightning charge, and hence even with good line insulation usually not more than one thirty-second of an inch. Wit h this striking distance means have been provided for effectually preventing the line-current from following the are; but the result accomplished by structures made in accordance with my invention is a readier path for the lightning, with no increased tendency of the line-current to follow the arc.

It has hitherto been supposed that lightning charges had infinitely great frequencies and that the readiest path of discharge was to conductors of small area. It has been found, however, that the facts are quite otherwise and that lightning will discharge much more readily across an air-gap where the surfaces bounding the gap are of large extent. A capacity or resonant effect seems to be established thereby,which assists the discharge. I have also found that the capacity for lightning of a metallic discharger varies inversely as the mass and that this law may be applied in practice in harmony with that wherein large discharging-surfaces are required. This increased capacity for lightning charges, due to a large surface and small mass, is not extended to the line-current. Since a large mass in a discharger is advantageous as a means for absorbing the heat generated by the arc if we reduce the mass of the discharger it is desirable to increase its surface in order to have a large area for heat radiation; but as the large surface is particularly desired because, other conditions being equal,the gap betweendischargers having the greater surface included in the gaps presents the least opposition to a discharge of lightning there is lost none of the advantages of .the dischargers having a larger mass and the resulting dischargers have a larger capacity. A maximum effect of this kind would be obtained by hollow spheres one within the other; but in practice it has been found necessary to have the inside surfaces of the dischargers exposed to facilitate the radiation of heat and prevent explosions caused by the formation of the arc. Furthermore,there may yet be sufficient metal in the discharger to act in a measure to conduct the heat away from the gap-surface and so prevent the renewal of the are by the line-current.

Figs. 1 and 2 of the drawings, a plan and vertical section, respectively, illustrate my invention as applied to a standard form of lightning-arrester, wherein a non-inductive resistance is placed in series with the airgap to prevent the line-current from continuing the are across the gap. I prefer this form, as it has proved the most efficient embodiment of my invention; 'butIdo not limit the application of the invention to the above or any other form of arrester.

A, B, and C are brass cupsor other hollow bodies suitable as dischargers, illustrative of the kind of dischargers set forth above, set Withinoneanotherand suitablymountedupon aninsulating-base t. Asuitably-insulated casing F surrounds the parts, and a cover X may be provided with suitable air-openings, if desired. A binding-post 1 is provided for one side of the line and asecond post 2,.to which the ground connection is made.

To increase the efficiency of the arres'ter, the short non-inductive resistance R, of'large surface, is placed in series with the cups. This resistance may be in the form of a carbon-rod and is supported in the brackets or clips 3 3.

Connection or contact strips D and D extend from each of the clips and are secured in contact with the cup 0 between the cup and the top of the insulating-base 4 and with the terminal 1. A second contact-strip E extends from post 2 along a groove in the base 4 to the metal post P, to which it is connected by screws 5. This strip is suitably insulated on the bottom, as shown at I. A plate G makes good electrical connection between the post and the cup A. An insulating-bushingt' separates the cups B and G from the post P, and plates 2', of insulating material, support the cups and keep them separated from each other and from the base 4:.

Many other suitable arrangements embodying the invention can be readily devised.

The operation of the arrester is as follows: When a lightning charge is induced in the line, it flows out through the resistance which opposes it in no substantial manner and across the air gaps which separate the cups to ground through the cups. The way across the air-gaps is made easy for the lightning discharge by the novel structure of the discharges described herein. The resistanceinterposes a bar to the line-current and the discharges quickly cool, so that there is no serious tendency for the line to follow the arc and the arrester promptly recovers its normal condition.

What I claim as new, and desire to secure by Letters Patent of the United States, is

1. The combination with acup-shaped electrode, of a second cup-shaped electrode of smaller dimensions, arranged within the first and separated therefrom by an air-gap between the bases and sides of the electrodes, theupper parts of the cups facing the same direction so that the surfaces are exposedfor radiation.

2. A lightning-arrester provided with cupshaped dischargers, having small mass and large surface area, and arranged one within another with their openings facing the same direction.

3. A lightning-arrester provided with a set of cup-shaped hollow dischargers arranged one within another, including an air-gap between the bases and sides, and their openings facing the same direction.

4. In alightning-arrester, the combination with cup-shaped dischargers arranged one within another, and so constructed that the heat generated by the arc will be radiated from exposed interior surfaces of said cupshaped dischargers.

5. A lightning-arrester provided with cupshaped dischargers, set one within another, including an air-gap between their bases and sides, their openings facing the same direction.

6. The combination in a lightning-arrest-er, of cup-shaped dischargers set one within another, their openings facing the same direction, and means for supporting said dischargers in normal electrical isolation with respect to each other.

7. A lightning-arrester, provided with cupshaped dischargers, nesting one within another and having large opposing dischargesurfaces,andcontinuousnon-dischargingsurfaces adapted to dissipate by radiation, the heat generated by the are.

8. A lightning-arrester, which comprises a cup-shaped discharger connected to line, and a similar discharger connected to ground and located in proximity to the first, so as to provide an air-gap of large area between their sides and closed ends, said dischargers having their open ends facing the same direction, in order to expose for radiation the inside of one discharger and the outside of the other.

9. Alightning-arrester, which comprises an insulating-base, a supporting-post, and a plurality of cup-shaped dischargers having openings in their bases through which the post extends, the dischargers being insulated from each other and nesting one within another, whereby an air-gap of large surface is included between them to provide a readier path for the lightning discharge, and the surfaces of the dischargers are exposed for radiation.

10. A lightning-arrester, which comprises an insulating-base, a conducting supportingpost, and a plurality of cup shaped dischargers having openings in their bases through which said post extends, one of said dischargers being connected with the post,the others being insulated from the post, all beinginsulated from each other, and each nesting one within another, whereby an air-gap of large surface area is included between them to provide a readier path for a lightning discharge, and the surfaces of the dischargers are exposed for radiation.

In witness whereof I have hereunto set my hand this 20th day of July, 1899.

- HENRY E. RAYMOND.

WVitnesses:

BENJAMIN B. HULL, CAROLYN L. HAYNES. 

